What are these "liberties" and "beliefs" of which you speak? I'm an American and think the place is run by lunatics and mafiosos and has been for my entire life. It's more obvious now, and the lunatics are vastly less competent and more ham handed and corrupt.
NATO was there to keep the Russians out and the Germans down. I don't support this organization at all in current year; it is simply a tool of US imperialism, and is spectacularly dangerous as US power fades and they add more shitty non-countries to it so some ding dong from Georgetown can win an award.
Can you tell me more about keeping the Germans down? I'm not sure I follow, but I'm probably misinterpreting what you mean by "down".
Without NATO, the Baltics would probably already be a part of Russia again.
The mainstream of American foreign policy is completely divorced from mainstream voters, which is one of the reasons for Trump's election: the foreign policy establishment has remained utterly impervious to American political sentiment for decades.
Most Americans are non-interventionist and veering on isolationist. They don't want to send foreign countries billions of dollars of foreign aid and they don't want endless US military expeditions. The US foreign policy establishment has ignored this at their own peril. They were able to neutralize Obama's foreign policy electoral platform; they haven't been so fortunate with Trump.
It's not very clear that American foreign policy has done anything to serve the interests of the average American in the past fifty years. It might have done great things for Europeans - I'm not a European, so I don't feel qualified to judge - but decades of American empire building have, if anything, hurt Americans, who have died in terrorist attacks caused by US foreign policy, been maimed in endless wars, and who have suffered from the economic globalization promoted by the foreign policy class. And frankly, I don't care about European interests or Crimean interests if they come at the expense of my interest.
Our current president is not the United States, despite his tendency to speak as if he is. I would argue he does not represent the main stream of American foreign policy and has continually fought against the majority opinion to protect institutions that preserve these freedoms and liberty (NATO / OTAN) and oppose actions that threaten said freedoms (annexation of crimea, etc).
September 11th had a huge impact on the country's view of civil liberties (rightly or wrongly is another discussion entirely) especially looking outward. While that might undermine the argument about America being a protector of liberties, I think it would be a mistake to believe that there is no belief held at all, or that America does not continue to fight for these beliefs. History is not something to rest on, but it does leave an indication of a country's intentions, I think.